Blocking callers completely

[teslonelf]

There is a number that I've set my phone to send to voice mail so that the phone wouldn't ring and it wouldn't wake me up 4 hours before I was supposed to get up. However, I still get an alert when I get new voice mail, which wakes me up anyway. I can't fall back to sleep if I get woken up, and I'm losing 4 hours of sleep every day. I can't put my phone on silent because I need to be able to be called for emergencies. Is there a way to completely block numbers, instead of just sending them to voice mail?